Development of the micro region pH sensor using Ag/AgIO<inf>3</inf> electrode method

Abstract

pH sensors are used for measuring pH of solutions etc in the beaker. It measures the whole part of samples collected inside the container. They are mostly made by a glass electrode method. Its merits are that has good potential reproducibility, and potential equilibrium time is faster than other pH measuring methods. pH sensors made by the glass electrode method are composed of glass electrode which has a glass thin film of approximately 0.05· mm· at the bottom, and reference electrode which has liquid junction at the bottom; besides silver chloride electrode was inserted in each electrode. Due to the complex design, the size becomes larger, thus it is required to downsize the pH sensor in order to measure the submicron size, such as cells which are around 10∼30[μm]. However, it is difficult to produce the smaller size by the glass electrode method, because KCl solution is used for internal liquid of a glass electrode and a reference electrode. Therefore, a new pH measuring method of Ag/AgIO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> electrode method was developed in our laboratory. Ag/AgIO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> electrode method does not require any internal liquid and is composed by an antimony electrode as the working electrode and an Ag/AgIO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> electrode as the reference electrode. Therefore, we considered that it is able to create a micro pH sensor.